Back Musles

Back Musles

1. 2) Deep muscles

   • 2) Short muscles
   • 1) Long muscles
     • Splenius capitis and cervicis
       • Action: 1) both act on many joints. 2) the Splenius capitis: alone: rotates the head, together: retract the head. 3) the Splenius cervisis: alone: bends the neck, together: extend the cervical vertebral region.
     • Erector spinae
       • iliocostalis (Lateral)
         • Action: Draw the ribs down
       • Longissimus (intermediate)
         • Action: Bilateral contraction extends the head, Unilateral contraction bends the head and turns the face.
       • Spinalis (medial)
       • Action: Extension of the vertebral column.
     • Transversospinales
       • Semispinalis
         • Capitis
         • Cervicis
         • semispinalis thoracis
       • Multifidi
         • Multifidi Lumborum
         • thoracis
         • Cervicis
       • Rotatores
         • Rotatores Longi
         • Rotatores breves

2. 1) Superficial muscles

   • 1) Muscles attached to the upper limb bones
     • First layer
       • Trapezius
         • Action: 1) Acts on ( he Sternoclavicular, Atlantooccipital, Intervertebral joints). 2) The upper fibers: elevate the Scapula makes slight rotation around the sagittal axis. 3) The inferior fascicles depresses the Scapula. 4) The unilateral contraction bends the head and the neck ipsilaterally. 5) Bilateral contraction tilts the head backwards.
       • Latissimus dorsi
         • Action: 1) Acts on the shoulder joint. 2) rotates the shoulder inwards. 3) depresses the raised arm. 4) pulls the lowered arm backwards and medially. 5) elevates the trunk and lower ribs when arms are raised.
     • Second layer
       • Levator Scapula
         • Action: 1) acts on Sternocalvicular joint. 2) elevates Scapula rotating it mediallly. 3) Flexes neck ipsilaterally when Scapula fixed.
       • Rhomboid major & minor
         • Action: 1) Acting together. 2) Draw the Scapula closer to the Vertebral Column, slightly elevate them.
   • 2) Muscles attached to ribs
     • Serratus posterior superior
       • Action: 1) acts on the costotransverse and Sternocostal joints. 2) elevates ribs.
     • Serratus posterior inferior
       • Action: Depresses and flexes the IX - XII ribs